1. Field of the Invention
This invention generally relates to image forming devices, and more specifically, a method and system for unloading media from image forming devices.
2. Description of the Related Art
Continuous forms printers refer to printers that use continuous forms media. The continuous forms media may include stacked sheets of paper which are folded in a box as shown in FIG. 1. FIG. 1 illustrates a box 1 which includes several stacked sheets 2, each sheet having a length (l) and a width (w). In this context, the term sheet refers to the portion of the media between two folds or perforation folds. It should be noted that in FIG. 1, each sheet represents a single form.
Within a continuous forms printer, the media travels along a media path (also referred to as a forms path or paper path). The media path generally refers to the entire route forms travel between the beginning state of being unused to the end state of a printed document. One characteristic of high speed continuous forms printers is that the media path is longer than the length (l) of a single sheet of paper.
FIG. 2 illustrates a media path 21 within printer 20. The media path 21 starts at 31 where paper is fed into printer 20 from an unused stack of paper 22 and ends at location 30 where printed paper is passed to a stacker 23. Location 24 along media path 21 represents the print start position and location 29 along media path 21 represents the print end position. It should be noted that media path 21 extends beyond print end position 29.
As a transport unit 28 transports the media between print start position 24 and print end position 29, an image may be transferred to the media via drum 26 (also referred to as an organic photoconductor cartridge) which receives toner from a developer 25. In general, once toner is on a sheet (i.e., immediately after the sheet has traveled pass a fusing system 27), that sheet is considered to be printed. The toner is permanently affixed to the media by heat and pressure from fusing system 27 before exiting the end of the media path at location 30.
In order to reduce the likelihood of paper jams caused by stacker 23, it is desirable to stack the media after printing with the folds in the same orientation as they were originally folded. If folding is done opposite the original fold direction, the jam rate may become unacceptably high.
Typically, the fold orientation of a continuous forms media is defined as having a xe2x80x9cfirst fold upxe2x80x9d or a xe2x80x9cfirst fold downxe2x80x9d. If one places continuous forms media on a flat surface in the direction the media will enter a printer, the media typically has xe2x80x9cmemoryxe2x80x9d in that the first fold will either bulge up or down slightly. If the first fold bulges up, then the media has a first fold up orientation and if the first fold bulges down, then the media has a first fold down orientation.
Once the continuous forms media exits media path 21 at location 30, the sheets may be stacked by a stacker. Stackers are typically attached to or positioned near a printer at the media exit location. Two common types of stackers are the gravity stacker and the power stacker. If the continuous forms media that exits the printer has strong memory, it can fall onto the floor and essentially stack itself in the fold orientation it had when it came out of a box. In this situation a gravity stacker may be suitable. On the other hand, if the continuous forms media that exits the printer does not have strong enough memory for the gravity stacker, or higher reliability is required, a power stacker may be suitable.
A power stacker includes a folding mechanism which must fold the media to match the fold memory of the media. This can be accomplished two ways, either the folding mechanism always folds in one direction with the media always being loaded into the printer with the same fold orientation, or whenever media is loaded, an operator must provide input as to the fold orientation of the media loaded.
When media is unloaded from media path 21, the last printed sheet is cut from the media. Furthermore, if stacker 23 requires that the media always be loaded in the same fold orientation, an additional unused sheet may also be cut from the media. For example, assume that stacker 23 requires that media always be loaded having a first fold up orientation. If the last printed sheet has a fold up orientation, then the next unused sheet has a fold down orientation. If the media was cut at the fold boundary between the last printed sheet and the first unused sheet, then the media would be reloaded having a first fold down orientation which would not meet the set-up requirements of stacker 23 and likely cause paper jams. Thus, in this situation, the media is cut after the next unused sheet so that the media can be reloaded having a first fold up orientation.
On the other hand, if stacker 23 does not require that media always be loaded in the same fold orientation, then for the example above, the media is cut at the fold boundary between the last printed sheet and the first unused sheet. Because the first fold orientation of the media has changed from first fold up to first fold down, stacker 23 needs to be informed of this change, which is typically done via operator intervention.
In certain situations, it is desirable to have multiple forms per sheet. For example, when printing checks, multiple checks may be printed on a single sheet. FIG. 3 illustrates an example where there are three forms per sheet. Sheet 33 includes forms 33a-c, sheet 34 includes forms 34a-c, and sheet 35 includes forms 35a-c. In FIG. 3, stacked sheets 33, 34, and 35 have been pulled from box 32 to illustrate that when the media is loaded starting with sheet 33, it has a first fold up orientation. As shown in FIG. 3, adjacent sheets 33 and 34 are separated by a fold perforation and adjacent sheets 34 and 35 are also separated by a fold perforation. Furthermore, adjacent forms within each sheet are separated by a perforation.
When media having multiple forms per sheet are used, it is likely that unused forms will be wasted when unloading the last printed form because mechanical stacking is based on the fold length of the sheet rather than a form. For example, assuming the stacker is set for a first fold up orientation and there are three sheets per form, if the first form (33a) of a sheet (33) having a fold up orientation is printed and there are no more forms to print, then in a first situation five unused forms are wasted and in a second situation two unused forms are wasted.
Five unused forms are wasted when the stacker requires media to always be loaded with the same fold orientation. In this situation, the media is cut after the two forms (33b-c) on the first sheet (33), a fold, and three forms (34a-c) in the next sheet (34). Based on this example, it is possible to waste five of the six forms when unloading.
Two unused form are wasted when the stacker does not require that the media always be loaded in the same fold orientation. In this situation, the media is cut after the two forms (33b-c) on the first sheet (33) and the stacker is reset to a first fold down orientation. Based on this example, the number of wasted forms is reduced from five to two forms; however, operator intervention is typically required to reset the stacker to change to first fold orientation.
In certain situations, it may be desirable to unload the media without wasting any forms and/or sheets. For example, when printing numbered forms, such as checks, the operators must manually account for the wasted forms.
An object of the present invention is to utilize full forms on consecutive print runs while automatically unloading print runs.
Another object of the present invention is to minimize the number of forms wasted during an unload operation.
A method of unloading media from a media path in an image forming device is described. The media includes a plurality of sheets with each full sheet having multiple forms such that a pair of adjacent forms includes a set of forms. A first form positioned at a print start position on the media path is advanced to a print end position on the media path. In response to an automatic unload request, the first form is cut from the media. Further in response to an automatic unload request, a next unused form is positioned at the print start position such that no forms are wasted between consecutive print runs due to an automatic unload operation. The first form and the next unused form are both from the set of forms.
A method of controlling a stacker for stacking media received from a media path in an image forming device is also described. The media includes a plurality of sheets with each full sheet including N forms. A first set of control values is provided to set the stacker for a first sheet. The first sheet represents a partial or full sheet. A second set of control values is provided to reset the stacker, if necessary, for a second sheet. The second sheet represents a full sheet.
An image forming device is described. The image forming device operates with media having multiple sheets with each full sheet including multiple forms. The image forming device includes a print engine having a media path with a print start position and a print end position. During an automatic unload operation, a last printed form from a first print run located at the print end position is removed from the media path. A first unused form is then positioned at the print start position in preparation for a subsequent print run. The image forming device also includes a printer controller coupled to the print engine. The printer controller controls the movement of forms along the media path during an automatic unload operation based on a first value. The first value represents a positioning orientation of a pair of adjacent sheets with respect to the print start position and a designated first fold orientation.
A printer controller is also described. The printer controller includes a memory device coupled to a processing unit. The memory device stores a first value and form definition values during an automatic unload operation. The first value represents a positioning orientation of a pair of adjacent sheets with respect to a print start position on a media path and a designated first fold orientation. The processing unit provides a first set of control values and a second set of control values based on the first value, the designated first fold orientation and the forms definition values. During the automatic unload operation, the first set of control values sets the stacker for a first sheet which is either a partial or full sheet, and the second set of control values sets the stacker, if necessary, for a second sheet which is a full sheet.